If I'm married I can no longer file single or Head of household. Even though my spouse has a disability and doesn't work.

[DoninGA]

If you are legally married you can only file as Married Filing Jointly or Married Filing Separately.  For tax purposes it is almost always better to file as Married Filing Jointly even if one spouse has little or no income.

[VolvoGirl]

Right,  But Joint is the best way to file even if  one person has no income.  A spouse is never a dependent.  You just file a Joint return for the both of you.  It has the highest Standard Deduction.  Does your spouse get a SSA-1099 from Social Security?  You need to enter it into your return.